1. Field of the Invention
This invention relates generally to a method and a device controlling the treatment, e.g., cleaning, sterilizing, and pre-filling the bottles, and more specifically to the cleaning of the interior of the bottles without the use of water or chemical solvents, such as peroxide.
2. Background Art
Various food and other substances subject to spoilage and/or contamination are commonly packaged in bottles in a fill-and-cap operation. Manufacturers of food products and beverages for human consumption typically package the beverage or food product. A variety of substances may be used to provide packaging for the products, including, but not limited to, plastics and glass. As a specific example, soft drinks typically are packaged in bottles formed from polyethylene terephthalate, otherwise known as “PET bottles.” However, other plastics are also well known to the beverage and food packaging industries for use as containers for food and beverage products.
In certain cases, the present practice in the industry, and in particular for the packaging of soft drinks, is to rinse PET bottles with water and or a cleaning chemical composition prior to filling the bottle with a soft drink. Before being filled with a liquid food or other products, bottles or similar containers, especially those made of glass or similar materials, are usually subjected to several preliminary treatment steps, particularly to a thorough cleaning and complete sterilization. To improve the microbiological quality of filled liquid foods, it is known to sterilize the bottles with heat, prior to the filling operation, to kill any germs that may be present and that are dangerous to the food being filled in the container. These operations may introduce steam, hot water or superheated water into the bottle to be sterilized by means of a sterilization installation with spray nozzles, which installation is generally connected as a separate machine before a filling machine, or, in individual cases, is integrated into the filling machine. However, such processes may be subject to incomplete sterilization, for example, as a result of control valve failure, or insufficient pressure, and thus bactericide of the germs in the bottles may be incomplete, or in severe cases, non-operational.
As is generally known, certain products, especially microbiologically susceptible products, require heat treatment so as to achieve a sufficiently good keeping quality. In the case of some products a heat treatment of less than 100° Celsius will suffice (this is referred to as pasteurization), in the case of other products temperatures exceeding 100° Celsius must be applied so as to achieve a good keeping quality of these products. This is referred to as sterilization. Either process may be referred to herein as sanitizing of the containers.
The desire for greater purity and longer shelf life for bottled products has led others to use a sanitizer, such as peroxide (H2O2) that is sprayed on the interior of the bottle prior to filling to reduce the likelihood of product contamination or spoilage due to microorganisms. As can be readily appreciated, the effectiveness of the sanitizer depends on thorough coverage of the interior of the container by the sanitizer spray and also on the complete removal by rinsing or other means of the chemicals prior to filling.
In spraying the sanitizer, several operating parameters can be varied to change the effectiveness of the spray coverage, such as the spray pattern, system operating pressure, sanitizer flow rate, temperature, sanitizer concentration, contact time, and the like, in order to increase the likelihood of complete sanitation. The final configuration of these parameters and the establishment of a complete spraying pattern of the inner surface of the bottles can reasonably assure effective sanitizer coverage. However, the use of chemicals in the sanitation process results in difficulties in cleaning of the sanitizing chemicals and also in the environmental disposal of used chemicals following the sanitizing operation.
The use of hot water or chemical disinfectants typically has not been considered suitable for rinsing PET bottles prior to filling because hot water or disinfectants could chemically or physically alter the characteristics of a PET bottle. Such alterations could render the bottles unsuitable for containing beverages, or may adversely affect the quality or taste of the beverage, or may even render the beverage unsuitable for human consumption.
Various devices and processes, not using unsuitable chemicals or excessively hot water, have been proposed for sanitizing containers such as bottles by contact with an ozonated rinse water. Ozone is highly reactive and is an effective oxidizing agent for sanitizing containers. Ozonated rinse water is preferable to untreated rinse water because it may be effective in removing microbes and other contaminants without changing the chemical or physical nature of the container. For example, Silberzahn U.S. Pat. No. 4,409,188 proposes a device for sterilizing containers that comprises a rotatable immersion wheel for immersing the containers in a bath of ozone and water. Other devices using ozone as a sanitizing agent have also been proposed. Hughes U.S. Pat. No. 5,106,495 proposes a portable water purification device using ozone as a treatment agent circulated by a pump through a venturi where the ozone is injected into the water, which is then returned to the tank after cleaning.
Some beverages, such as lemonades, mineral waters containing CO2 or more acidic liquids, do not require hot filling, i.e., an increased temperature of the product, at the time of bottling due to their natural acidity. When this type of beverages is bottled, it is sufficient that adequate hygienic operating conditions are used so as to be able to produce containers being sterilized to remove any microbiological elements. However, if beverages containing alcohol and/or CO2 are of such a nature that specific microorganisms may thrive and consequently the beverages become unfit for human consumption, additional plant equipment may be required for controlling these microorganisms, e.g. external rinsing, disinfection possibilities and sterile media.
To provide a thorough cleaning of the inside of a bottle, several methods have been used, some of them in conjunction with the sanitizing step. That is, a hot water rinse if properly directed into a bottle having a downwardly facing opening, where in a large number of bottles are being transported through a conveyor system. An example of such a cleaning arrangement is disclosed in U.S. Pat. No. 5,363,866. A jet nozzle arrangement is taught which provides an aeration and distribution of a cleaning agent at successive stations in the conveyor line.
Another consideration of those prior art methods and systems that have a fluid or jet stream that is directed into the enclosure defined by the container walls, and especially those which intrude there into by inserting a nozzle or other means of producing a jet flow into the enclosure itself, a possibility exists for introduction of extraneous matter and/or contamination into the bottle, which presently requires measures to avoid the possibility of such contamination.
Other methods for either cleaning or sanitizing containers, and more specifically, plastic bottles, are known, but all of these are similar to those prior art methods and systems described above. What is needed is a cleaning and sanitizing procedure that is efficient, effective and does not produce undesirable effluents or other residual elements, while simultaneously providing resource conservation and sustainability.
None of the prior art systems or methods known heretofore teach a non-aqueous method that does not utilize chemicals or other environmentally unfriendly methods of cleaning and/or sanitizing the inner surface of a bottle.